Degenerate submanifolds of pseudo-Riemannian manifolds are quite difficult to study because there is no preferred connection when the sub- manifold is not totally geodesic. For the particular case of degenerate totally umbilical hypersurfaces, we [...]
This paper introduces Gray-tensors on lightlike hypersurfaces M n+1 of signature (0, n), (n ≥ 1) and investigates on their basic properties in connec- tion with their null geometry. In particular, we show that there is an interplay between existen [...]
ATINDOGBE COMLAN CYRIAQUE [1], BERARD BERGERY LIONEL [2], TOSSA JOEL [3],
We study Weyl structures on lightlike hypersurfaces endowed with a conformal structure of certain type and specific screen distribution: the Weyl screen structures. We investigate various differential geometric properties of Einstein–Weyl screen st [...]
ATINDOGBE COMLAN CYRIAQUE [1], BERARD BERGERY LIONEL [0], OGOUYANDJOU KOLADÉ SIMPLICE EPHREM CARLOS [3],
We show that on a non-minimal lightlike hypersurface with nullity degree 1 , there exists a unique null transversal (normalizing) vector eld with prescribed calibrated divergence, for which the induced connection and the Levi-Civita connection of [...]